Manufacture of carbon black



June 14, 1938. E. BILLINGS Er Al.v 2,120,541

MANUFACTURE 0F CARBON BLACK June 14 1938. E. BILLINGS l-:T AL 2,120,541

MANUFACTURE 0F CARBON BLACK Filed NOV. 16, 1952 2 Sheets-Sheet 2 I170671102 M En. M

7M Af.

Patented June 14, 193s MANUFACTURE F CARBON BLACK Edmund Billings,weston, and Harold n. offut't, Winchester, Mass., assignors to GodfreyL. Cabot, Inc., Boston, Mass., a corporation of MassachusettsApplication November 16,1932, Serial No. 642,850

29 Claims.

This invention relates to improvements inthe manufacture of carbonblack. In one aspect it consists in improvements in the processdisclosed in our copending application Serial No. 623,184,

s flied July 18, 1932, for manufacturing carbon black in the form ofgranules of relatively high apparent density. The present application isa continuation in part of that application as to -all common subjectmatter. Y

l0 'Ihis invention, aswell as that of our said copending application,rests-upon the discovery that by subjecting carbon black particles in adry state to multi-directional pressure, at the l same time maintainingthem in a state of turbul lence, they are caused to agglomerate witheach other and to associatetogether in a novel form, viz.. the particlesare built up'system'atically and progressively into spherical granules,relatively tenacious in structure, `relatively .non-coherent andnon-adherent of surface and of an apparent density of more than 18'pounds percubic foot. Ihe novelproduct thus produced possesses strikingcommercial advantages. In the first place, it is substantially dustlesslin that nearly all of its particles are agglomerated into granules ofsubstantial slze and density. In the second place, the density and thenon-adherent -character of the' surface of the granules reduces theapparent viscosity of the mass and permits the carbon black to beconveyed through pipes by gravity or by streams of air, to betransported in 'tank cars and to be stored in bulk. Beside being muchmore cleanly for the consumer to handle, ,the novel product whenproperly mixed I with ingredients such as rubber disperses as completelyand perfectly-as commercial carbon black of forms heretofore known. I

The novel product above described is the subv lect matter of U. S.Letters Patent No. 1,957,314,

40 granted May 1, 1934 upon our copending, application. The processherein disclosed comprises one of several whereby that product may bemanufactured economically on a commercial basis.

AThe precise steps leading to the production of this new product ofmanufacture may be varied to some extent so long as each nucleus orcenter is subjected to impact or pressure from substantiallyeverydirection. One manner of securing to satisfactory conditions is tomaintain the carbon black for a. suflicient time in a `state approachingperfect turbulence underconditions of 'turbulent pressure such that eachparticle has freedom of motion and is associated with other particles insuiiicient number to insure the multi- (Cl. 134-60) ,w

directional pressures orv impacts required. For

example, a charge' of commercial carbon black may ,be converted into theform of relatively hard, dense an'd spherical grains by beingproperlyagitated in a drum so that the requisite 5 pressures yresult fromtheimpact of the agitating blades, the impact of one particle againstanother and the impact of the particles against the walls of the drum.

Another manner in which the desired results 10 maybe secured is bytreating a charge of commercial carbon black in a mill of the characterof .a ballmill. In this case, therequisite pressures may be derivedprincipally from the rolling impact of the particles as they drop'froml5 particle to particle in rolling down thesurface of the shifting massin the mill or from the impact of particles against` the rotating walls.

In whatever apparatus the -carbon black is treated, the'process ofconversion to the dense 20 granular form is expedited by including inthe mass a quantity of carbon black in its final form, .that is to say,a mother or priming charge in said granular form. The explanation ofthis probably is that an increased number-of pressure 25 and impactsupplying units is thereby provided and the requisite degree ofturbulence facilitated so that the agglomeration,` shaping andcompacting of the individual dense spherical grains takes place morerapidly than under conditions where- 30 in the building up of the carbonblack granules is brought about in an amorphous mass. The introductioninto the process of this seeding or priming step is advantageousprincipally because it reduces the time required for effecting a com- 35plete agglomeration or conversion of the charge but it is not otherwiseessential.

Commercialcarbon black in bulk is very viscous and for this reasonoifers'considerable resistance to the turbulent motionabove described,40 especially when treated in relatively large bulk. We have discoveredthat the speed of the process is somewhat enhanced by intensifying theimpact nature of this turbulence and that such 'improvement may beeectively brought about 45 by subjecting thecarbon black to turbulentpressure between opposing surfaces relatively mov- "able toward and pasteach other to agitate and' impact' the black therebetween in a turbulentmanner. This action brings the particles com- 5b I prising the blackinto a most intimate and bombarding relation, whereby they arernorespeedily and completely compacted into the relatively hard and denseform above described. The eiliciency of the process .and the consistencyand sa value of the product also depend to a very lar-ge extent upon theuniformity of the treatment 'of 38 all the parts of lthe carbon blackduring this operation and for this reason we also agitate or move theblack transversely of and simultaneously with the turbulent movementimparted as above explained. This latter agitation serves to circulatethe bulk of black continuously during the treatment and thereby tends tokeep the product uniform at all times. We also-prefer to oppose somewhatthis latter agitation, whereby such movement serves not'only to keep theproduct uniform but also aids in the impacting of the blackinto itsfinal dense form. Thus the* black is agitated in `two directions at anangle to each other and, while being kept of a uniform consistency, isimpacted into dense form bythe opposition to its movement in saiddirections and the -impacts and encounters.

The nature of the invention will be best undertion of one form ofapparatus which is well adapted for the production of spherical graincarbon black in accordance with our improved process.

'In the accompanying drawings,

Fig. 1 is a vertical sectional view through an apparatus embodying ourinvention;

Fig. 2 is a plan view partly in section on line 2-2 of Fig. 1; f Fig. 3is a fragmentary view kon an enlarged scale illustrating'diagrammatically the hori'-l zontal movement of the carbon blackparticles in the apparatus; and

Hg. 4 is a fragmentary view in vertical section illustratingdiagrammatically the vertical movement of the carbon black particlesinthe apparatusi The apparatus comprises a stationaryvertically-disposed tank or drum I0 which is formed from a cylindricalshell flanged and bolted to bottom and top plates I2 and I4. Dependingfrom the bottom plate is a boss providing' a vertical bearing I6 andbrackets providing horizontal ybearings I8 and 20. Rotatably mounted inthe vertical bearing I 6 are a sleeve 22- and a shaft 24, the

sleeve and shaft extending upwardly into -the drum Il).

Mounted on-the upper endof the shaft 24 and within the drum Ill is arotatable cage 25 sup-v v cular in cross section. The top ends and theintermediate portions of the rods are connected together bysimilarconcentric bands34, 35 and-3B; Also carried by each circular rowof rods 32 are one or more spirally arranged straps or blades 38.

An inverted cage 39, similar to the cage 25 supported on the collar 26and just described, is

mounted in stationary position on a plate 4i! secured within the upperend of 'the-drum I8. This stationar-y cage 39 comprises a plurality oi.'cir- -cular rows of rods 42, corresponding to the rows of'rods'32 andspaced concentrically, carried by andI depending from the plate 40.'I'he rods 42 in each row are .connected together by three or more bands44 and each row of. rods also has mounted thereon one or morespirally-arranged straps orblades 48, `the stationary straps 46 beingpitched in the same direction as andl arranged in a manner similar tothe movable straps A relative rotary movement is provided between thetwo cages by rotating the shaft 24 on which is mounted the cage 25. Ashaft 5D, having a driving pulley 52 thereon, is mounted in the bearingsI8 beneath the drum I0 and on the opposite endl of this shaft is a gear54 arranged in mesh with a relatively larger gear 58 on a parallel shaft58 journaled in the bearings 20. A spiral gear GII on-the shaft 50 isarranged to mesh with a like gear 62 on the vertical shaft 24 and a worm64 on the shaft 58 is in mesh with a worm gear 68 on the lower end ofthe sleeve 22. Through these connections the pulley 52 is connected torotate the first described cage`25 in a counterclockwise direction asshown by the arrow (Fig'. l) and to rotate the sleeve 22 in the samedirection at a relatively slower speed.

The sleeve Vlli isprovided with a flange 'I0 to which is secured ascraper having a horizontal portion I2 extending radially outward alongthev bottom -wall of the drum and a vertical portion 14 extendingupwardly along the side wall of the drum, a substantial clearance beingprovided between both parts of the scraper and the vfunction of thescraper is to remove from the bottom and side walls of the drum the.carbon black which would otherwise build up thereon in the form of acoating or shell and which would otherwise become thick enough to extendwithin lthe path of movement of the stra-ps 38 and seriously vary theclearance between the side Walls and the elements. 32. It will beunderstood lthat to permit the product to build up on these walls wouldnot only deleteriously affect the desired turbulent motion of theproduct, reduce the effective capacity of the apparatus and increase thepower consumption unnecessarily, but would produce Va shearing andbreaking up of the treated product and thus to some extent defeat thepurpose of. the treatment. The sleeve rotates the scraper at a reducedspeed which is suiicent to keep the walls free from any substantialaccumulation of the black, and by this arrangement shearing of thegrains by the rotary cage or the scraper is substantially eliminated andthe total amount of shearing in the apparatus is limited to a minimum.

The charge of flocculent carbon black may be introduced into the drumthrough an opening provided through the top wall at 8|) and the flnishedproduct may be drawn oif through a discharge pipe 82 in the bottom plateI2, a damper valve 84 being provided within the discharge Pipe- Inoperating the apparatus herein disclosed, .the drum I 0 may be fillednearly to its capacity l45 R.. P. M. andra scraper speed of 11A; R. P.M.,

have been found to be quite satisfactory. The result of this operationis that the charge of carbony black is stirred or churned into a stateof turbulence in which the particles-.are subjected to multi-directionalpressure by impact with other particles and by impact `against the opiments are constantly changing as the elements which, in like manner, notonly `opposes such upposing and repelling surfaces and againstthe ywallsof the drum. Under `these conditions there occurs an agglomeration ofthe particles resulting in a progressive and systematic building up ofthem into spherical granules having hammered or impact-formed surfaceswhich present the striking characteristics of high density andnonadherent, free-flowing contact with each other.

Ingeneral, it-may be stated that the apparent density of the carbonblack may be brought to approximately 30 pounds per cubic foot. At thisdensity the granules may be 250 meshv or larger in diameter.

In the light of our present knowledge, we may Suggest one theory of whattakes place within the-drum to cause the carbon black to `assume its newand relatively dense form by reference to Figs. 3 and 4 of the drawings.'Irhe stationary elements 42 are arranged alternatelyv with themovingelements 32 and the charge of carbon'black surrounds and entirely fillsthe space between these elements. As the elements 32 move `relative tothe elements 42 (Fig. 3), they tend to carry the black in a masstherewith but such movement of the black is opposed by the stationaryelements 42. The result is that cones 86 and 81 of carbon black formboth forwardly and rearwardly of the elements 32' and move along withthese elements, while cones 88 and 89 of carbon black form bothforwardly and rearwardly of the elements 42 remain stationary therewith.The carbon black intermediate the elements 32 and 42 (indicated by line90 kof particles in Fig. 3) is in a state of turbulence, the

black adjacent to the elements 32 moving nearly as fast'asthose elementsand the carbon black adjacent tothe elements 42 remaining nearlystationary; The relative positions of the ele- 32 approach and recedefrom the elements 42 and, due to this action, the particles of carbonblack are alternately being brought into most intimate and bombardingYrelation with each other whereby they are compacted into the relativelydense form of the finished product and intoa relatively loose relation,wherein they are free to rearrange themselves for the next impact. Thusthe carbon black particles are intermittently subjected tomulti-directional pressures or impacts and are relativelyl rearrangedbetween the successive impacts, such impacts vor pressures thereby notoccurring twice in succession v in the s'ame direction.

Simultaneously with the above action. the spiral straps 38 areacting'constantly to move portions of the carbon black mass upwardly andthereby keep the product uniform from bottorn to top. It will beunderstood that sinceV the pressure of the carbon black increases withits depth, the nature of its turbulent and bombarding action willcorrespondingly vary from top to bottom.'

By constantlyV moving the black from bottom to top, the entire charge isVbeing continuously passed through the apparatus and thereby given auniform treatment throughout. movement of the carbon black by thestationary spiral straps 38 is, however, opposed by the spiral straps 46whichare secured to the elements 42. The result of this arrangement issomewhat illustrated in Fig. 4. Rotation of the spirals 38 tend to'raisethe carbon black upwardly, while centrifugal Vaction may also somewhatmove the black outwardly. That portion of the black 1ocated intermediateeach two adjacent and concentric'spirals 38 is intercepted by a spiral4G This upward.

ward movement but tends ,to move the black downwardly, it beingunderstood that in the apparatus illustrated, the mass of carbon blackas a whole is also rotating in the drum though ata greatly reducedspeed. When the shaft 24 and the cage 254 invthis apparatus varerotating at 45 R. P. M., the mass of carbon black ordinarily rotates atabout 4 R. P. M. 'I'hus the spirals Il and 46 not only serve to keep theproduct uniform from top to bottom but also set up an opposing motion ofthe carbon black in a substantially vertical direction, similar to thehorizontal motion set up by the elements 32- and 42, which materiallyaids in developing the necessary pressure of impact of the black and itsconversion into its nal dense form. This movement and opposing action ofthe black are illustrated by the arrrows and the lines 92 of blackparticles in Fig. 4.

When the treatmentl of acharge of carbon black .has been continued inthis manner from to 120 minutes, it will be found that practically theentire charge has been converted from its original occulent condition tothe granular form abovedened, in which all'the grains are substantiallyspherical in their general shape but in Which they vary somewhat insize. This finished product may be withdrawn and used advantageouslyWithout further treatment. 'Howevel rfor convenience in operation weprefer to sepaproportion of carbon black in these portions depends uponthe size of the mesh of the sifting screen used and we have operatedvery satisfactorily with a mesh which results in two substantially equalportions. The coarser portion may be withdrawn at this stage as finishedproduct, while the fine portion may be used as a priming charge for thesucceeding batch. The fine portion is, accordingly, returned to the chy.mber and suilicient untreated carbon black added to form a new batch. l

While we have referred to the treatment of each batch as requiring aperiod of from 60 to minutes, this may be varied within certain` limits.It should be noted, however, that if the coarse size grains are notseparated in the manner above described, then the grains formed may,exceed the stable dimensions and will thereupon appears to be of lsomeimportance in'carrying out our process and we have found that a radialspacing or clearance of about one inch between adJacent elements 32 and42 is quite satisfactory. The spiral straps 3 8 and 46 are arranged in asimilar manner and may be located on the outer sides oftheirbaiileelements for convenience in manufacturing the cages. The speed ofrelative rotation between the cages is also of importance insuccessfully carrying out the process and, as above stated.,we havefound that a relative rotation between 27 and 45 R. P. M. is verysatisfactory. y

In addition to the characteristics of relatively high density andnon-coherent surface, -the carbon black granules produced as aboveoutlined are relatively tenacious in their structure. They cannot becrushed between the ngers by normal pressure, although they may bereadily crushed against a hard surface or by rubbingwhich subjects themto shearing stress between the fingers.

built up in a dry state, without assistance of.

binders, solvents, liquids, tars o r other additions, either temporarilyAor permanently present in such a manner as to transform flocculentcarbon black into substantially dustless tenacious granules, theparticles of which are united only bytheir own cohesive force withsufficient tenacity of structure to resist disintegration whentransported in bulk. l

Having thus described ourinvention, what we claim as new and desire tosecure by Letters Patent is:

l. A process of compactingdry flocculent carbon black, which consists inturbulently agitating the carbon black in a dry state in a mannercausing agglomerationko the particles into relatively tenacious,self-sustaining and. dense grains of substantially spherical shape thatcan be trans- Y portable. in bulk without disintegration, and thenagitating the agglomerated grains thus formed until they are' brokendowninto substantially dustless fragments of irregular shape, said fragmentsretaining substantially the same physical properties as the densegrains.

2. A .processfof producing carbon black form of granules of carbon blackof sumcient density and cohesion to withstand vhandling in -bulk withoutdisintegration, which consists in impacting the particles of fiocculentcarbon black Vin a dry state between opposing surfaces relativelymovable toward and past each other ina manner maintaining'the particlesin a state of pronounced turbulence and thus causing systematic andprogressive agglomeration'of the particles into tenacious granules ofthe character described.

3i A process of producing carbon black in the Kform of granules ofcarbon black of suilicient density and cohesion to withstand' handlingin j `bulk without disintegration, which consists in impacting theparticles of fiocculent carbon black in a dry state between opposingsurfaces relatively movable toward and past eachother in a. mannermaintaining the particles in a state of pronounced turbulence and thuscausing a systematic and progressive building up of the particles intotenacious granules, and simultaneously movingthe particles in adirection transverselyl to the relative movement of said surfaces.thereby keeping the product uniform throughout the,

mESS.

4. A process of producingl carbon black in the form of granules ofcarbon black of sufllcient density and cohesion to withstand handling inbulk without disintegration, which consists inturbulently impactingparticles of occulent carbon black in a dry state by propelling surfacesmoving in a circular direction and opposing such movement of theparticles by other surfaces loin the black, consisting in impacting theparticles therecated out of the path of movement of the rstmentionedsurfaces, thereby systematically and progressively building up theparticles into gran- I ules of the character described.

`5. A process of producing carbon black in the form `of granules ofcarbon black of sufficient density and cohesion to withstand handling inbulk without disintegration, which consists in forcing groups ofparticles of occulent carbon form of granules of carbon black'ofsuflicientk density and cohesion to withstand handling in bulk withoutdisintegration, which consists in subjecting particles of dry flocculentcarbon black in a mass to violent turbulence in which occur successiveand rapid impacting impulses causing the systematic and progressiveagglomeration of the particles into tenacious, non-adherent granules,alternated with relaxing impulses causing a rearrangement oftheparticles in the mass.

A7. A process of producing carbon black inthe form of granules of carbonblack of sufficient density and cohesion to withstand handling in bull-r'without disintegration, which consists in causing particles of dry'carbon black: in a mass to ow in spaced concentric zones, andsimultaneously subjecting the particles to recurring pressure inrelatively transverse directions, thereby maintaining the particles ina' state of pronounced turbulence for a time suilcier'it to cause thesystematic and progressive a'gglomerationof the particles intosubstantially spherical granules of the character described.

8. A process of compacting flocculent carbon of in a dry Lstate by andbetween opposing surfacesextending into and surrounding a mass oftheparticles being treated and relatively movable toward and past eachother in a manner maintaining the particles in a state of pronouncedturbulence and thus causing systematic and progressive agglomeration ofthe particles into relatively dense,v non-adherent granules capable ofwithstanding handling in bulk without substantial disintegration, andsimultaneously moving the particles and granules in a directiontransversely to the relative lmovement of said surfaces, thereby keepingthe granules substantially uniform ,in

size throughout'the mass.

l 9. A process of compacting carbon black, which consists in impactingthe particles of occulent carbon black in a dry state between opposingsurfaces thereby maintaining the particles in a state of pronouncedturbulence for a time sufiicient to cause systematicand progressiveagglomeration of the particles into relatively dense, non-adherentgranules capable of withstanding handling in bulk without substantialdisintegration, separating the resulting product into relatively coarseand fine portions, and-using the relatively fine portions as a primingcharge in succeeding operations.

10. A process of producing carbon black in the form of granules of purecarbon black of sumcient density and cohesion to withstand handling inbulk without disintegration, which consists in subjecting occulentcarbon black of commerce tinulng such agitation until said carbon blackassumes the form of relatively tenacious selfsustaining granules.

11. A process of producing carbon black in the form of granules of purecarbonblack of sufficient cohesion to withstand handling in bulk withoutdisintegration, which consists in subjecting particles of ilocculentcarbon black in a dry state to multi-directional impact with othercarbon black particles, by turbulent agitation of a dry mass offiocculent carbon black, and continuing such agitation until said carbonblack agglomerates into granules which `are self-sustaining butdisintegrate readily under shearing pressure.

12. A process of producing carbon `black in granular condition, whichconsists in mixing a' the mixture, and continuing such agitation untilparticles of fiocculent vcarbon black agglomerate with the granularcarbon black to form a carbon black in the form of granules capable ofwithtanding handling in bulk without disintegralon.

13. The process of manufacturing substantially spherical grain carbonblack, which consists in maintaining dry particles of ilocculent carbonblack in a state approaching perfect turbulence, whereby the particlesare freely subjected to symmetrical impact and caused to cohei'e toother granules and are thus built up progressively into relativelydustless, substantially spherical granules which in bulk have a lowviscosity and a density of over 20 pounds per cubic foot.

. 14. The process of manufacturing spherical grain carbon black whichconsists in turbulently agitating a dry charge of flocculent carbonblack particles at moderate temperature, in such a manner as to subjectcertain particles symmetrically to free impact pressure of" otherparticles,

thus building them up progressively and sys` tematically intosubstantially spherical granules ofl an order of approximately 200 meshin diameter and capable of withstanding handling in bulk withoutsubstantial disintegration.

15.'The process of imparting dense granular and tenaciouscharacteristics to theflght, iluffy carbon black of commerce, whichconsists in subjecting particles of the latter, in a dry state, toturbulent agitation, thus compacting the'particles by impact and causingthem to unite by im pact-generated cohesion into granules of pure carbonblack of sufllcient density and cohesion` to withstand handling in bulkWithout disinte- 16. The process of producing a dense granular carbonblack which consists in mixing a charge of fiocculent carbon black withcarbon black which has been agglomerated into granules and densled, andthen turbulently a'gitating the.

mixture to cause the systematic and progressive agglomeration of theiiocculent carbon black upon said granules into larger, substantiallyspherical granules, land then applying repeated multi-directionalpressure to such granules lmparting a smooth surface iinish thereto andmaking them capable of withstanding handling in buik without substantialdisintegration.

17. The process of producing dense, spherical carbon black whichconsists. in mixing a charge `of iiocculent carbon black with granularcarbony black and then turblently agitating the mixture in a drycondition so that the nocculent particles contact with the granules withsuiiicient velocity to unite therewith to form substantially sphericalgranules of pure carbon black which in bulk have a low viscosity and a`density ofover 20 pounds per cubic foot.

18. The process of producing a dense, dustless granular carbon blackwhich consists in mixing a charge of occulent carbon black with apriming of granular carbon black, and then turbulently agitating themixture at a temperature below that at which oxidation of the carbonblack occurs to cause the flocculent carbon black to agglomerate withthe granular carbon` black and by subjecting the agglomerates tointermittent multi-directional pressure, to convert them into suclfagitation until said mixture has taken the form oi granules.

2U. A process of producing carbon black in the form of a'substantiallydustless free flowing mass of agglomerates of sufficient density andcohesion to withstand handling in bulk without disintegration, whichconsists in subjecting particles of relatively tenacious,self-sustaining vilocculent carbon black in a dry state to turbulentagitation by rolling and tumbling and thereby producing saidsubstantially dustless mass ol the character described.

21. A process of producing from a mass oi' flocculent carbon black inthe dry, loose state in which it is delivered from the ordinary boltingand sifting apparatus of a carbon black plant, av

substantially dustless mass of free iiowing coherent agglomerates ofcarbon black of suineient density and cohesion to withstand handling inbulk without disintegration, which consists in subjecting suchliocculent carbon black to turbulent agitation, and continuing suchagitation un`- til such carbon black assumes the form of said relativelytenacious self-sustaining granules.

22. A process of producing from a mass of flocculent carbon black in thedry, loose state in 'which it ls delivered from the ordinary bolting andsifting apparatus of a carbon black plant, a substantially dustless massof free flowing coherent agglomerates of commercially pure carbon blackof suillcient density and cohesion to withstand handling in bulk Withoutdisintegration, which consists in adding agglomerated granules ofcarbon' black to a mass of the iiocculent carbon black and subjectingthe mixture to turbulent agitation by rolling and tumbling.

23. A process of transforming a mass of dry, flocculent carbon blackinto a substantially dustless Vmass of free flowing, relativelytenacious, self-sustaining granules of substantial density and cohesion,which consists in adding agglomerated granules of carbon black to a massof flocculent carbon black and then subjecting the resultingv mixture toturbulentagitation to form therein and `therefrom granules of carbonblack of the' character described which are capable of withstandinghandling in bulk without substantial disintegration.

24. A process of producing from a mass of ilocculentcarbon black in theydry, loose state in v which it is delivered from the ordinary bolting.taining` granules having an apparent density of v over 20 lbs. percubic foot.

25. A process of transforming a mass of i'locculent carbon black into asubstantially dustless, free owing mass of relatively tenacious,selfsustaining granules, transportable in bulk without disintegration,which consists in subjecting said mass to turbulent agitation andtherebyagglomerating substantially all of said mass oi ilocculent blackinto relatively compact'granules of the character described,substantiallyy iree in bulk of unagglomerated particles' and having anapparent density of not less than 2O lbs.. per cubic foot.

26. The process of transforming' flocculent, powdery carbon black into acollection of relatively sturdy, self-'sustaining granules, saidcollection being characterized by being free iiowing .and substantiallyfree from unagglornerated particles or dust, which consists in'subjecting said fiocculent carbon black to turbulent agitation wherebythe particles of said carbon black are brought into multi-directionalbombarding relation with each other, causing impact-genu eratedcohesions between particles of such- Patent No 2,120, 5141.

EDMUND BILLINGS ET AL.

turbulent agitation until said granules are sui..- ciently sturdy towithstand handling in bulk without disintegration.

27. The process of making granular lcarbon black, said product beingcharacterized by being iree flowing and substantially free ofunagglomerated particles or dust, substantially as described, whichconsists in adding agglomerated granules of carbon black to a mass offlocculent powdery carbon black, and subjecting said mixture toturbulent agitation thereby creating multi-directional impacts betweenparticles and granules, whereby the particles are caused byimpact-generated cohesions to cohere to the said granules or to eachother, and continuing said turbulent agitation until all the dustyparticles have been thuscaused to cohere into granules sufficientlysturdy to withstand handling in bulk without disintegration.

2 8. A process of producing carbon black in the form of granulesofrsuiiicient density and cohesion to withstand handling in bulk withoutdisintegration', which consists in subjecting occulent carbon black ofcommerce in a dry state to turbulent agitation by lifting the carbonblack in one area after another and allowing it to fall freely in aclosed container and continuing such agitation until the black assumesthe form of relatively tenacious self-sustaining granules.

.29. A process of producingl carbon black in the form of granules ofsufficient density and co-l hesion to withstand handling in-bulk withoutdisintegration which consists in subjecting ilocculent carbon black ofcommerce in a dry state to turbulent agitation bypassing a series ofblades angularly through a mass thereof in a closed container, andcontinuing such agitation until the carbon black assumes the form ofrelatively tenacious self-sustaining granules.

\ EDMUND BILLINGS.

HAROLD H. O'FFU'I'I'.

CERTIFICATE OF- CORRECTION.

June lll,

It is hereby certified that error. appears in the printedspecificntionof the above numbered. 'patent requiring correction as follows: Page lfirst column, lines 52 and 55 strike out the words ,'junder conditionsof turbulent pressure auch page 2, second column, line 65, for "primary'`read. priming; page 5, first column, line 66, strikey out the word"stationery" and insert the same before the syllable "spi" in line 67;a'nd that the 'said Lettere Patent:v should be read. with'thesecorrections therein-thatvthe eme nay conform to the record of the casein the Patent' Office,

'- signed and sealed this 19th any or' July, A. D; 1938.

, (Seal) Henry van Arsdnle, Acting Comissioner-.of Patente.

withstanding handling in bulk without substantial disintegration.

24. A process of producing from a mass of ilocculentcarbon black in theydry, loose state in v which it is delivered from the ordinary bolting.taining` granules having an apparent density of v over 20 lbs. percubic foot.

25. A process of transforming a mass of i'locculent carbon black into asubstantially dustless, free owing mass of relatively tenacious,selfsustaining granules, transportable in bulk without disintegration,which consists in subjecting said mass to turbulent agitation andtherebyagglomerating substantially all of said mass oi ilocculent blackinto relatively compact'granules of the character described,substantiallyy iree in bulk of unagglomerated particles' and having anapparent density of not less than 2O lbs.. per cubic foot.

26. The process of transforming' flocculent, powdery carbon black into acollection of relatively sturdy, self-'sustaining granules, saidcollection being characterized by being free iiowing .and substantiallyfree from unagglornerated particles or dust, which consists in'subjecting said fiocculent carbon black to turbulent agitation wherebythe particles of said carbon black are brought into multi-directionalbombarding relation with each other, causing impact-genu eratedcohesions between particles of such- Patent No 2,120, 5141.

EDMUND BILLINGS ET AL.

turbulent agitation until said granules are sui..- ciently sturdy towithstand handling in bulk without disintegration.

27. The process of making granular lcarbon black, said product beingcharacterized by being iree flowing and substantially free ofunagglomerated particles or dust, substantially as described, whichconsists in adding agglomerated granules of carbon black to a mass offlocculent powdery carbon black, and subjecting said mixture toturbulent agitation thereby creating multi-directional impacts betweenparticles and granules, whereby the particles are caused byimpact-generated cohesions to cohere to the said granules or to eachother, and continuing said turbulent agitation until all the dustyparticles have been thuscaused to cohere into granules sufficientlysturdy to withstand handling in bulk without disintegration.

2 8. A process of producing carbon black in the form of granulesofrsuiiicient density and cohesion to withstand handling in bulk withoutdisintegration', which consists in subjecting occulent carbon black ofcommerce in a dry state to turbulent agitation by lifting the carbonblack in one area after another and allowing it to fall freely in aclosed container and continuing such agitation until the black assumesthe form of relatively tenacious self-sustaining granules.

.29. A process of producingl carbon black in the form of granules ofsufficient density and co-l hesion to withstand handling in-bulk withoutdisintegration which consists in subjecting ilocculent carbon black ofcommerce in a dry state to turbulent agitation bypassing a series ofblades angularly through a mass thereof in a closed container, andcontinuing such agitation until the carbon black assumes the form ofrelatively tenacious self-sustaining granules.

\ EDMUND BILLINGS.

HAROLD H. O'FFU'I'I'.

CERTIFICATE OF- CORRECTION.

June lll,

It is hereby certified that error. appears in the printedspecificntionof the above numbered. 'patent requiring correction as follows: Page lfirst column, lines 52 and 55 strike out the words ,'junder conditionsof turbulent pressure auch page 2, second column, line 65, for "primary'`read. priming; page 5, first column, line 66, strikey out the word"stationery" and insert the same before the syllable "spi" in line 67;a'nd that the 'said Lettere Patent:v should be read. with'thesecorrections therein-thatvthe eme nay conform to the record of the casein the Patent' Office,

'- signed and sealed this 19th any or' July, A. D; 1938.

, (Seal) Henry van Arsdnle, Acting Comissioner-.of Patente.

